Laptop processor around 60%, no major processes running

hi to you all

After a couple of days of simple web browsing and listening to music on my laptop
i've found out it has become really slow.
it can easily top up to 85 % usage

this is what avast found:

system tweeks
--disable fast user swithing
--set CPU priority to prefer foreground apps

system parameters
user tweeks
--forground lock time out
--hung app time out
--similar to waittokillservicetimeout but not for shutdown
--menu show delay
--wait to kill service timeout
--disable beeping on errors
--disable contacting microsoft web service to resolve file association
--disable usage of NFTSs tracking feature for LNK resolution

My avast is free, so i dont really trust paying 24$ for PC cleanup.
i use Ccleaner instead, but does not seem to find the problem
ill be very happy if you guys help me get rid of that thing

thank you !

PC-laptop hp g60 550ca, windows 7 home 64



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